Manufacture of fertilizers



Patented May 30, 1933 PATENT QFFICE DAVID SHIELDS,- OF EDGEWORTH, PENNSYLVANIA MANUFACTURE OF FERTILIZER-S so Drawing. Application filed April 22,

This invention relates to the manufacture of fertilizers, and constitutes an improvement on the methods of manufacturing fertilizers from coal of various grades disclosed in my Letters Patent of the United States No. 913,929., granted to me March 2,

1909, and Letters Patent of the United States No. 1,212,573, granted to me JanuarylG, 1917.

An object of the present invention is to so treat coal with heat, water, agitation, and salts in solution as to obtain a maximum disintegration of the coal and a uniform rim pregnation of the disintegrated coal with salts. r

A further object of the invention is to so mix the disintegrated coal with clay that particles of clay and coal are commingled to form a substantially uniformmass throughout, and so that the clay as well as the coal is impregnated.

In so far as the general use of finely divided coal heated and agitated with a mixture of salts in solution is concerned, my

V present process conforms to the practice as outlined in my two prior patents. According to my improved practice, however, I subject the coal to a higher temperature, capable of increasing the disintegration of the coal, and at a critical point in the process limited by agglomeration of the coal and segregation of salts crystallized from solution, I restore the fluidity of the mass and effect a complete and uniform distribution of salts through the body of the disintegrated coal.

As typical of my improved process, I may pursue the following exemplary detail procedure. To 1,140 pounds of coal which is finely divided to pass through a twenty mesh screen I add in a kettle 48 gallons of subterranean salt water, which is the salt water naturally flowing from oil or gas wells, or. mines. This volume of water when mixed with the coal is sufficient to form therewith a fluid mass. This mixture is agitated in the kettle, and the kettle is heated directly to a temperature suflicient to boil off the salt water of the mass. This temperature will 50 be initially somewhat in excessof 212 F;

1932. Serial No. 606,912.

and as the heating continues the temperature will rise until the boiling point of a saturated solution of the salts is reached. This temperature will be in the range of 2&0 F. to 260 F. During this primary period of heating and agitation, which will normally continue for three to five hours more or less, the fluid mass is constantly agitated, and a progressive disintegration of the coal particles may be observed.

As the saturated solution of salts boils, the salts will begin to precipitate onthe coal and at the water level in the kettle. When the crystallization and deposition of the salts becomes marked it will be noticed that 55 at this stage there is also present a tendency for the coal to agglomerate in the kettle.

It should be emphasized that the concentrating action should not'now be continued,

as beyond this point there is a tendencyfor (0 the coal to cake in the kettle or even to be partially distilled. Distillation of the coal, resulting in coking, or even a mere caking of the coal, seriously interferes with subsequent handling of the'mass, and detracts from its value as a'fertilizer. Segregation of precipitated salts in the mass of coal, which would also occur by continued evaporation, not only detracts from the value of the mass as a fertilizer, but also causes the portions of coal containing an undue quantity of salts to be positively detrimental to plant life.

At the above stage of the process I therefore add a quantity of water which is substantially free of mineral matter to the mass in the kettle. This soft water, which as naturally occurring is generally known as pond or freestone water, I add in a volume sufficient to restore the fluidity of the mass and to distribute theprecipitated salts, either by redissolution or by mechanical action, through the mass of coal particles- With the quantity of other ingredients given by way of example, this volume of fresh water should not be less than 4: gallons, and may be as great as 10 or 12 gallons.

After the addition of the soft water heating and agitation is continued for a relatively short period, as for example for two 1% proper point, as evidenced by marked crysa tallization of salts from solution, and by increasing the fluidity of the mass under conditions of'continued heat and agitation, particularly fine and porous particles of the coal uniformly receive and absorb salt solu- 20 tion and fine particles of precipitated salts.

It should be understood that the above conditions are exemplary, since the relative proportions ofcoal and salt water and the initial fineness of the coal maybe varied within relatively wide limits. I may also, ifthe subterranean salt water be not readily available, artificially prepare a substantial equivalent of such water containing chlorides of sodium, calcium and magnesia, together with other minerals in the general proportion range in which they naturally occur. In preparing such solution I may also add such other salts, as for example potassium salts, which I may consider desirable. I may also use various carbonaceous materials 'of natural occurrence such as bituminous, anthracite, or cannel coal,

" ofthe mass, with continued heat and agitation after the maximumheating effect without caking or coking of the coal has been obtained.

t should be understood that the secondary step of heating and. agitating the coal mass after the addition of soft water should not be continued to a point at which a marked crystallization of the salts is vto be observed.

In order to make upmy complete fertilizer the impregnated mass of coal is mixed with a finely dividedclay, preferably plastitc clay. As a specific example I have added coal in the above noted quantity to 800 pounds of clay divided to such fineness that it will pass througha screen of ten meshes to the inch. The commingling of the impregnated coal and the clay may be effected in various ways, to give a uniform mixture of the coal and clay. My preferred inherently limited temperatures.

procedure, however, is designed to lessen the mechanical mixing required for uniformity, and to cause an impregnation of the clay as well as the coal with the salts which are present.

In following my preferred procedure I run the mass of coal, which is still fluid at the end of my secondary heating and agitating step, onto the finely divided clay in a suitable container, without permitting the fluid coal mass to cool prior to its addition tothe clay. The clay and the hot fluid mixture of disintegrated coal and water are then readily commingled uniformly, and salts contained in the water which have not been taken up by the coal are available to impregnate the clay.

WVhile the commingled mass of coal and clay is in pasty condition, I prefer to pellet the mixed mass by forcing it through the meshes of a screen or sieve. This completed mass is then ready for immediate use as a 1 soil food without any necessity for a preparatory seasoning prior to its use.

a In this improved process I take advantage of the relatively high boiling range of salt solutions to subject the coal to higher but As conducted according to my preferred procedure, I impregnate the clay, as well as the coal, with the salts of the subterranean salt water or its equivalent.

The relatively high temperature to which the coal is subjected results in a disintegration more complete than might be obtained by longer heating at a lower temperature, ill effects of unduly high temperature are avoided, and a maximum and uniform impregnation is obtained.

The critical point, or more properly the critical stage has been defined in terms of observable conditions in the batch or mass undergoing treatment. It is necessary that the treatment he carried into the stage of marked observable crystallization in order that the desired extreme disintegration of the coal may be obtained. The observation of such condition gives a more accurate check on the coal condition than would be possible by setting a definite time period for the treatment, since it provides inherent compensation for such-variations in concentration' and boiling point of the brine as may occur in practice.

It may be noted that, coincidently with marked crystallization, agglomeration of the coal particles begins. The further treatment with soft water checks the agglomerating tendency present at the critical stage, and at the end of the final soft water treatment, the coalmass is in suitable fluid condition to be commingled with the clay. Additionally, the'final treatment results in further reducing the. coal intoparticles of the desired fineness and porosity, and causes a uniform distribution of the salts through the coal.

The complete process results in the forma tion of a fertilizer the coal constituent of which is in such condition that it may most readily impart its beneficial effects to the soil. By the term coal as used throughout the specification and claims I intend to designate also the related materials containing carbonaceous matter such, for example, as peat and lignite.

I claim as my invention:

1. The herein described process of manufacturing fertilizer which consists in mixing a coal in finely divided condition with suflicient subterranean salt water to produce a fluid mass, heating the mass to the boiling temperature of the subterranean salt water, continuing the boiling of the sub terranean salt water accompanied by agitation to a point at which a marked crystallization of its contained salts is observed and initial agglomeration of the coal occurs, at such stage adding to the mass soft water suflicient to restore the fluidity of the mass and distribute the salts therethrough, completing the disintegration of the coal and the impregnation thereof by continued heating accompanied by agitation, limiting the continuance of the secondary heating step to a point short of evaporation of the water sufficient to produce agglomeration of the coal, and mixing the impregnated coal with finely divided clay.

2. The herein described process of manufacturing fertilizer which consists in mix ing a coal in finely divided condition with suflicient subterranean salt water to produce a fluid mass, heating the mass to the boiling temperature of the subterranean salt water, continuing the boiling of the subterranean salt water accompanied by agitation to a point at which a marked crystallization of its contained salts is observed and initial agglomeration of the coal occurs, at such stage adding to the. mass soft water sufficient to restore the fluidity of the mass and distribute the salts therethrough, completing the disintegration of the coal and the impregnation thereof by continued heating accompanied by agitation, limiting the continuance of the secondary heating step to a point short of evaporation of the water suflicient to produce agglomeration of the coal, drawing off the fluid mixture of disintegrated coal and water, and mixing the coal and water while hot with finely divided clay.

3. The herein described process of treating fertilizer which consists in mixing a coal in finely divided condition with water containing a relatively great percentage of mixed salts in solution, the water being sufficient in volume to produce with the coal a fluid mass, heating the mass to the boiling temperature of the salt water, continuing the boiling of the salt water with agitation to a point at which a marked crystallization of its contained salts is observed and initial agglomeration of the coal occurs, at such stage adding to the mass soft water in volume suflicient to restore the fluidity of the mass and distribute the salts therethrough, completing the disintegration of the coal and the impregnation thereof by continued heating accompanied by agitation, limiting the continuance of the secondary heating step short of evaporation of the water suflicient to produce agglomeration of the coal, and mixing the impregnated coal with finely divided clay.

4. The herein described process of treating fertilizer which consists in mixing a coal in flnely divided condition with water containing a relatively great percentage of mixed salts in solution, the water being sufficient in volume to produce with the coal a fluid mass, heating the mass to the boiling temperature of the salt water, continuing the boiling of the salt water with agitation to a point at which a marked crystallization of its contained salts is observed and initial agglomeration of the coal occurs, at such stage adding to the mass soft water in volume suflicient to restore the fluidity of the mass and distribute the salts therethrough, completing the disintegration of the coal and the impregnation thereof by continued heating accompanied by agitation, limiting the continuance of the secondary heating step short of evaporation of the water suflicient to produce agglomeration of the coal, drawing off the fluid mixture of disintegrated coal and water, and mixing the coal and water while hot with finely divided clay.

In testimony whereof I have hereunto set my hand.

DAVID SHIELDS. 

